Understand how it is possible to measure your biological age – 12/27/2023 – Science

If you’ve ever been to a high school alumni reunion, you know that some people seem to age faster than others. Twenty-five years after graduation, one classmate may look a decade younger than the rest, another a decade older.

“People know this intuitively,” said Nir Barzilai, director of the Institute for Research on Aging at the Albert Einstein College of Medicine, “but they don’t understand that it’s biology that we’re trying to figure out.”

Scientists are working to quantify this phenomenon and assign a number to a person’s “biological age” by looking at their cellular health rather than how old they are. Some of these measurements are now marketed as direct-to-consumer blood tests.

But before you spend hundreds of dollars to find out how old you really are, make sure you know what you’re paying for. Experts warn that while these tests are interesting in theory and can be valuable research tools, they are not ready for prime time.

How do you measure biological age?

Researchers define biological age as “the accumulation of damage that we can measure in our body,” said Andrea Britta Maier, co-director of the Center for Healthy Longevity at the National University of Singapore. This damage comes from natural aging as well as our environment and behaviors.

The concept is often attributed to British physician-scientist Alex Comfort, known for the book “The Joy of Sex,” who published a paper on the idea in 1969. But for decades, scientists didn’t know how they could measure someone’s biological age. .

An important breakthrough occurred in 2013, when Steve Horvath, professor of human genetics and biostatistics at the University of California, Los Angeles, proposed the use of a “clock” based on the emerging field of epigenetics. Throughout our lives, our DNA accumulates molecular changes that activate and deactivate various genes. Horvath analyzed these changes in thousands of people and developed an algorithm to determine how they correlate with age.

These changes occur naturally as we age, said Jesse Poganik, a Harvard Medical School instructor who researches biological aging; they can also be accelerated by behaviors that affect health, such as smoking and excessive alcohol consumption.

As a result, biological age estimates have been linked to things like life expectancy and health, he said.

Why You Should Be Careful With Consumer Testing

Several companies now sell tests for around US$300 (R$1,500) that use this technology to calculate your biological age by analyzing your blood or saliva and comparing changes in your epigenome to population averages.

But experts warn that epigenetic clocks can’t really tell you much about your own health. This is because they were designed to evaluate large groups of people, not individuals. Consequently, your results may be unreliable.

At a recent conference where Horvath spoke on the subject, an audience member said he had taken two different tests and was given two different ages, 10 years apart. Horvath said the man should have saved his money.

“I guess you could say the best of them are not completely useless,” said Daniel Belsky, an associate professor of epidemiology at Columbia University who developed an epigenetic clock himself. “But these are not yet tried-and-true clinical tools, so they are more for the curious.”

Another problem with testing is that it’s not clear what to do with the results. Scientists don’t know how to reverse someone’s biological age — or if it’s even possible.

This is partly why epigenetic clocks were developed in the first place. Researchers hope to use them in clinical trials for anti-aging interventions to measure possible changes in the life spans of hundreds or thousands of people at once.

None of this has stopped companies from selling these tests alongside personalized health and lifestyle recommendations, as well as supplements that claim to reverse an individual’s biological age.

Giving a new perspective to old information

Epigenetic clocks are not the only products on the market that promise to measure biological age. Some companies offer a panel of conventional blood tests that you can take at your doctor’s office, such as cholesterol or hemoglobin A1C, a marker for diabetes.

They say that because many of these numbers increase as we age, they can be used as a proxy for a person’s biological age. For example, if you are 45 years old, but your cholesterol levels look more like a 50-year-old, the test results may say that your biological age is older than your 45 years.

Whether blood marker tests actually track biological age as opposed to general health is up for debate. But an advantage of this type of test is that it measures factors that can be modified; We know how to reduce blood sugar levels through medication and lifestyle changes, for example. In contrast, epigenetic age is more of a black box.

“Expanding access and using more frequent testing to optimize health seems very reasonable to me,” Poganik said in an email. But, he added, “any claims of accurate biological age determination at the individual level should be approached with caution.”